One of the things that sets Barack Obama apart from most politicians is how much can be learned from listening to his speeches.

The president is sometimes criticized for the volume of his public appearances, and, in truth, he is out there orating a lot.

But we learned in the course of his campaign -- and it was reinforced in this first year of his term -- that it's a mistake to think of these talks as routine. They have no equal in providing insights into the way his mind works and the context that guides his decisions.

The striking thing is the consistency with which he places concrete actions into the broadest historical or philosophical setting, and how much he is influenced in his decision-making by the reach of his intellectual exercise.

This first struck me during the crisis in the primaries when the racially provocative views of his longtime pastor, the Rev. Jeremiah Wright, came to public attention. In his Philadelphia address, Obama took the first steps to separate himself from Wright, but he also somehow managed in the pressure of a hard-fought campaign to compose what is likely to be seen as the most significant essay on race delivered by any public figure since the days of Lyndon Johnson and Martin Luther King Jr.

His immediate task at West Point was to announce the conclusions of his agonizingly long review of Afghan strategy and to explain his doubly controversial decision to send in 30,000 more U.S. troops but start pulling them out by July 2011.

Beginning to answer all the questions that had been raised by the leaks of internal debates during the previous three months would have been enough of a challenge. But Obama insisted on placing his decision in its historical context -- as a response to the instigators of the Sept. 11 attacks later overtaken by the war in Iraq -- and then in its strategic context, as a central piece in the unfinished struggle to stabilize the vital Pakistan-Afghanistan region.

Seeing it in that light, it was perfectly clear why Obama had decided to defy the prevailing wishes of his own party and raise the stakes.

In Oslo, the obvious challenge was to explain why a president leading a nation engaged in two wars should be singled out for the peace prize. Rather than avoiding the issue or burying it in cliches, Obama took it head-on, beginning in the first minute of his speech and devoting half the text to that question.

He focused on the meaning in today's world of the ancient concept of "the just war" and found himself arguing that, contrary to the wishes of those who awarded him this prize, "We will not eradicate violent conflict in our lifetimes. There will be times when nations -- acting individually or in concert -- will find the use of force not only necessary but morally justified."

Afghanistan is such a case, he said, as was the Persian Gulf War to repulse Iraq's invasion of Kuwait. But he made no such claim for the war in Iraq that George W. Bush launched, and he insisted that the many moral compromises made by the previous administration in the war on terrorism were unjustified as well.

This was not a speech tailored to his immediate audience. He even dared to argue directly with the ghost of King, asserting that "a nonviolent movement could not have halted Hitler's armies."

But it gave listeners a clear sense of where and why Obama would draw the line on using or threatening force in international bargaining. And it explained as well what had seemed the sometimes contradictory invocation of strong sanctions against Iran and the readiness to invite negotiations with Tehran.